justin@justin-XPS-13-9360:~/work$ python3 mapreduce.py
spawning batch 1
result -> {'x': 2, 'y': 6, 'z': 8}
result -> {'x': 6, 'y': 8, 'z': 14}
spawning batch 2
result -> {'x': 1, 'y': 2, 'z': 3}
result -> {'x': 1, 'y': 2, 'z': 3}
- x: 2
y: 6
z: 8
- x: 6
y: 8
z: 14
- x: 1
y: 2
z: 3
- x: 1
y: 2
z: 3
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October 21, 2019 09:50
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Python mapreduce pattern
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""" | |
- http://skipperkongen.dk/2016/09/09/easy-parallel-http-requests-with-python-and-asyncio/ | |
""" | |
import asyncio, concurrent.futures, copy, math | |
def run_parallel(worker, requests, callback, batchsz): | |
async def main(batch): | |
with concurrent.futures.ThreadPoolExecutor(max_workers=20) as executor: | |
loop=asyncio.get_event_loop() | |
futures=[loop.run_in_executor(executor, worker(**kwargs)) | |
for kwargs in batch] | |
for struct in await asyncio.gather(*futures): | |
callback(struct) | |
n=int(math.ceil(len(requests)/batchsz)) | |
loop=asyncio.get_event_loop() | |
for i in range(n): | |
print ("spawning batch %i" % (i+1)) | |
batch=requests[i*batchsz:(i+1)*batchsz] | |
loop.run_until_complete(main(batch)) | |
loop.close() | |
def run_many(requests, batchsz): | |
def worker(**params): | |
def fn(): | |
resp=copy.deepcopy(params) | |
resp["z"]=params["x"]+params["y"] | |
return resp | |
return fn | |
results=[] | |
def callback(result): | |
print ("result -> %s" % result) | |
results.append(result) | |
run_parallel(worker, requests, callback, batchsz) | |
return results | |
if __name__=="__main__": | |
import random | |
random.seed(13) | |
requests=[{"x": int(10*random.random()), | |
"y": int(10*random.random())} | |
for i in range(4)] | |
response=run_many(requests, batchsz=2) | |
print () | |
import yaml | |
print (yaml.safe_dump(response, | |
default_flow_style=False)) |
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pyyaml |
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